1. Field of the Invention
The present invention relates, in general, to a circularly polarized ceramic patch antenna having an extended ground for a vehicle, and more particularly to a circularly polarized ceramic patch antenna having an extended ground for a vehicle, in which the extended ground is formed under a patch antenna, has a predetermined thickness, is formed of a metal conductor in a shape that is the same as that of the patch antenna, and is electrically connected to a ground plane formed on a board, thereby reducing a null point to improve radiation efficiency.
2. Description of the Related Art
FIGS. 1 and 2 show schematic and detailed configurations of a ceramic patch antenna 10 for a vehicle installed on a conventional shark fin antenna for a vehicle. As shown in FIGS. 1 and 2, the conventional ceramic patch antenna 10 includes a dielectric 11 formed of ceramic on a board 1 having a feeder circuit and a ground plane of a vehicle antenna, a radiator 12 formed of a quadrilateral metal thin film on the dielectric 11, a ground 13 formed of a metal thin film under the dielectric 11, and a feeder 14 connecting the radiator 12 and the feeder circuit disposed on the board. The conventional ceramic patch antenna for a vehicle is small in size and light in weight, but it has the problem that, since its antenna performance is limited by the occurrence of a null point, its use is restricted to global positioning system (GPS) antennas that do not require high antenna performance.
Thus, there is an urgent need for a technology that in reality has a high degree of applicability and is able to reduce the null point occurring at the ceramic patch antenna for a vehicle to provide various radio communication services such as the reception of digital satellite radio broadcasting.